Another day, another Internet startup with a billion dollar valuation.

This time it’s Auction.com, an Irvine, Calif.-based online real estate marketplace that reportedly has raised $50 million from Google Capital at a $1.2 billion valuation.

Auction.com claims to be the country’s leading online real estate marketplace with $26 billion worth of residential and commercial property sold via the platform since it started six years ago. The company says it is attracting 20 million unique visitors per month, which compares to the 70 million visitors that Zillow attracted in January.

The $1.2 billion valuation would put it just ahead of Trulia, which is traded on the New York Stock Exchange and was valued at $1.16 billion as of Monday. Zillow, meanwhile, is valued at $3.3 billion. Google Capital is the search giant’s new private equity arm.

Zillow traffic

“At Auction.com, we believe that bringing buyers and sellers together with an easy, transparent platform yields the true value of any real estate asset, whether it be a luxury home, a multi-story Class A office building, an entry-level foreclosed home, or a self-storage facility,” the company writes on its Web site. Auction.com takes a five percent cut on transactions taking place on the marketplace.

Auction.com is not directly competitive with Zillow or Trulia, though the new funding from a big player like Google (which has tinkered in the online real estate arena in the past) could signal that competition may be looming. Auction.com president Jake Seid tells TechCrunch that sites like Zillow and Trulia are complimentary, noting that “Trip Advisor is to Priceline as Zillow is to Auction.com.”

In other words, Auction.com is more directly focused on the transaction.

Even still, the online real estate category is seeing some interesting activity right now. Last month, Japan-based Recruit Holdings purchased online real estate company Movoto, the 18th most visited real estate site in the U.S. At the time, Recruit’s manager for U.S. operations, Shiro Takeuchi, told Inman that they had aspirations to be the “No. 1 online real estate service in the U.S.” And last November Seattle-based Redfin pulled in a $50 million venture round of its own, perhaps setting up an IPO.

So, here’s what we’ve got to say about all of this recent activity, taking from the classic Nelly song: “It’s getting hot in here.”

John Cook is GeekWire's co-founder and editor, a veteran reporter and the longest-serving journalist on the Pacific Northwest tech startup beat. Follow him @johnhcook and email john@geekwire.com.